Wrapping roll for bending machines



March 2, 194& W.-E. KANE WRAPPING ROLL FOR BENDINQ MACHINES 2Sheets-Sheet Filed June 6, 1940 Imzerrr n12 MLLIAME. KANE v ATTBRME?March 2, 1943. w E. KANE 2,312,988

WRAPPING ROLL FOR BENDING MACHINES Filed Jun 6, 1940 2 Sheets-Shqet 2IHvENTnR WILLIAM EKAJYE ATT uRNEY Patented Mar. 2, 1943 WRAPPING ROLLFOR. BENDING MACHINES William E. Kane, Syracuse, N. Y., assignor to Kane& Roach, Ina, Syracuse, N. Y., a corpora- UNITED STATES PATENT OFFICE ofthe two fixed rolls.

tion of New York Application June 61 1940, Serial No. 339,085

13 Claims.

My invention is directed to anew type of wrapping roll for metal bendingmachines of the type adapted for bending rods, bars, and structuralshapes such as angles, channels, etc., into arcs, circles, and helixes.Although I have developed my invention with special reference to thistype of heavy metal bendingmachine, it is obvious that a hollow rollwould likewise be useful in sheet metal bending machines.

In the ordinary shop, the pyramid type bending machine is preferred asthis type of machine is readily adaptable for bending material todifferent radii. It has, however, many disadvantages. The pyramid benderordinarily includes two rolls fixed in relation to each other and athird roll which may be moved toward and away from the fixed rolls. Byadjusting the distance of the movable roll to the fixed rolls,'materialcan be bent to different radii. The three rolls are ordinarily of thesame size and are geared together so that the three rolls have the samesurface speed. As the rolls are ordinarily or cornparatively smalldiameter, the bending is accomplished by exerting pressure at threepoints against the material that is being formed. As a result, at thebeginning of the bend a flat section be produced. Likewise, as the endof the material passes through the three rolls, there will be a similarfiat section. The result is that true circles or complete arcs cannot beproduced by the pyramid machine. It therefore becomes necessary eitherto curve the fiat sections in a supplementary operation or to cut themo'fi.

There are two general types of pyramid benders. 'In one type, theadjustable roll is carried on a swing arm. In the swing arm type orpyramid bending machine, there is only one position of the swing armwhere the center of the adjustable roll is equally distant from thecenters As the swing arm is moved from this position to produce bends ofdifierent radii, the adjustable roll will be nearer one of the fixedrolls than to the other. In the second type of pyramid bending machine,the adjustable roll is carried on sliding ways in order that the centerof the adjustable roll will always be equidistant from the centers ofthe fixed rolls no matter to what position the adjustable roll is moved.If it is attempted to convert the pyramid bender to a wrapping machineby substituting a wrapping roll for the adjustable roll, it becomesnecessary to change the gearing connecting the adjustable roll to thefixed rolls in order that the surface speed of the-adjustable roll andthe fixed rolls may be the same. This is impractical in the swing armpyramid ty e bender. If such adjustment is not made, the surface of thework will be scuffed because of the different surface speeds of therolls. Furthermore, if the pyramid bender be of the swing arm type, theuse of a wrapping roll on the adjustable arm would be objectionablebecause with wrapping rolls of difi'erent "diameters the center of theWrapping roll will be closer to one of the fixed rolls than to the otherroll, with the result that the bending arc of the wrapping roll would be.decreased and much of its usefulness destroyed.

In order to overcome this difiicult'y and to protime an are having auniform bend throughout its length or to produce a true circle, anothertype of machine is used which is known to those skilled in the art as awrapping type machine. A wrapping type machine ordinarily includes tworolls fixed with relation to each other and a third movable spindlewhich may be moved toward and away 'from the first two rolls. 'The thirdroll is carried by the movable spindle. To produce complete truecircles, the third run is made have ing a diameter somewhatapproximating the .diameter of the finished work. In the ordinary case,the diameter of the third r011 will'be smaller than the diameter of thefinished work because the metal tends to spring back somewhat afterbeing bent. However, the wrapping machine has the advantage that insteadof having only three points of bearing against :the work, the work ispressed against the wrapping roll for a distance which is approximatelythe length of the arc bounded by a center line drawn from the center ofone of the fixed rolis to the center of the wrapping roll on one side,and a center line drawn from the center of thesecond fixed roll to thecenter of the wra ping roll. It is thus seen that the material is bentagainst the surface of the wrapping roll through the length or this arc.The result is that the finished article is given a uniform bendthroughout ite length and comparatively true circles may be produced. 7

There are two types .of wrapping machines made. In the first type, thetwofi-xed rolls are power-driven and the wrapping roll is an idler. Thistype of machine is suitable .for a wide variety of work but where thebend is of a compar-atively short radius and the material 'tobe formedis heavy, there .maynot be suflicient .frictional drive positively to.force the material through the rolls, with the result that excessiveslippage occurs and the surface of the material being formed may bebadly scuffed. To overcome this difiiculty, the second type of wrappingmachine provides power drive to the three rolls including the wrappingroll. However, when work of different diameters is to be finished, it isnecessary to use different diameter wrapping rolls. This requires achange gear system in order that the surface speed of the Wrapping rollmay approximate the surface speed of the two fixed rolls. In any case,the capacity of the wrapping type machine is limited to the largest sizeof wrapping roll that may be mounted in the machine and this in turn islimited by the length of the sliding ways.

There is a third type of bending machine in use which is sometimesdesignated as a four roll pinch bender. This machine has two opposeddriving rolls between which material to be formed is fed. On either sideof the driving rolls are two idler rolls which are adjustable. Thearrangement of the rolls is roughly diamond shapedthe two pinch rolls:on opposite points of the diamond and the two idler rolls being at theother two points of the diamond. The pinch type machine gives a morepositive drive to the material than does the wrapping machine having anidler roll, but is subject to the similar limitations as to bending asis the pyramid type machine.

' The main object of my invention is to provide a new type of roll whichmay be used on any of the types of bending machines heretoforedescribed.

Another object of my invention is to provide a hollow roll which may beused on a pyramid or pinch type bending machine to convert the machineinto a wrapping type machine.

Another object of my invention is to provide a hollow roll for a pyramidbending machine of the swing arm type, which roll is self-centering.

Another object of my invention is to provide ahollow roll for a wrappingtype bending machine, which roll will maintain correct surfacespeedwithout the necessity of changing gears.

Still another object of my invention is to providea hollow wrapping rollfor a bending machine, which roll can be made'of any desired diameterwithout regard to the ordinary capacity of themachine. j V

A still further object of my invention is to provide a hollow wrappingroll for use on a bending machine, which roll can be produced cheaply.

Another object of my invention is to provide a'ho'llow wrapping roll fora bending machine, which roll will be of a minimum weight.

'Other objects and advantages of my invention will appear from thefollowing specification and drawings, in which:

Figure l is a plan view of a swing arm type pyramid bending machinehaving vertical spindles and showing the wrapping roll of my inventionin use, with the upper shroud plate removed for clarity.

Figure 2 is a diagram of the gearing for driving the three rolls of thebending machine shown in Figure 1.

Figure 3 is a section, parts being broken away, taken on the line 33 ofFigure 1.

Figure 4 is an exploded perspective view of the hollow roll of myinvention showing the shroud plates.

Figure 5 is an elevation, parts being broken away, of a wrapping typebending machine showing'the use of my hollow wrapping roll, with theshroud plate carried by a fixed roll.

Figure 6 is a diagram showing the driving gearing of the wrappingmachine shown in Figure 5.

Figure 7 is an elevation of a pinch type bending machine, parts beingbroken away, showing the use of the hollow wrapping roll of myinvention.

Figure 8 is a section, parts being broken away, taken on the line 8-8 ofFigure 5.

Referring now more particularly to Figure 1, the pyramid bending machinecomprises a frame H) in which are journaled the vertical shafts II and[2. The shafts H and I2 carry the rolls [3 and I4, respectively, whichare constructed to rotate with the shafts by means of the keys l5 andIS. A swing arm I! is pivoted to the frame I!) by means of the shaft l8so that the swing arm moves in a horizontal plane. Adjustment of theswing arm I! is made by means of the screw l9 and nut 26. One end of thescrew [9 is pivotally secured to the frame I 0. The

screw projects through a suitable aperture 2| provided adjacent the endof the arm I1 so that when the nut 20 is turned the swing arm may bedrawn in toward the axis of the rolls l3 and M. The shaft 25 isrotatably mounted in the swing arm I! and carries the roll 26 which iscon strained to rotate with the shaft 25 by means of the key 21. Shaftsll, l2 and 25 are geared together by means of the train of gears shownin Figure 2. Power means (not shown) is connected to and drives the geartrain. The gears are selected so that the shafts ll, I2 and 25 rotate atthe same speed.

The hollow wrapping roll of my invention comprises a cylindrical shell30 which may he slipped over the roll 26. In order that the roll 30 maybe restrained from axial movement with reference to the shaft 25, twoshroud plates 3| and 32 are provided. In adapting the pyramid bendingmachine to use my hollow wrapping roll, the roll 26 is removed, lowershroud plate 3| is slipped over the shaft 25, the roll 26 is thenreplaced and the hollow roll 39 is placed over the roll 26 resting onthe shroud plate 3|. Shroud plate 32 is then placed on the shaft 25 andthe whole assembly secured by means of the nut 33 which isscrewed on athreaded upper portion 34 of the shaft 25. Clearance is provided betweenthe shroud plates 3| and 32 and the hollow roll 30 so that the roll 30is free to move independently of the shroud plates. The hollow roll 30is made with an outer diameter suitable for the work to be formed. Swingarm I1 is adjusted by means of the nut 20 and the work 35 is fed betweenthe hollow roll 30 and the fixed rolls l3 and 14. Work 35 is thus bentaround the wrapping roll 30 in the same manner as in a standard wrappingbending machine.

As the roll 26 is driven by the shaft 25, the roll 26 in contact withthe inner surface of the shell 30 will act as a frictiondriver to rotatethe hollow roll 30. Thus, with the use of a hollow roll placed over theroll 26, due to the internal friction drive of the roll 26 against theinner surface of the roll 30, the machine is adapted to bend heaviermaterial to smaller radii than is a standard wrapping machine having anidler wrapping roll. Furthermore, it is to be noted that since thehollow roll 30 is free to move eccentrically with relation to the shaft25 and the roll 26, the roll will auto maticallyralign itself withreference to the shafts II and I2 regardless of the positionrof theswing arm I1. If the roll 26 is of the same diameter as the rolls l3 andl4,,it is obvious that the outer surface of the hollow roll 36. wouldhave a higher surface speed than either the rolls l3, [4 or 26. As aresult, there will be some slip inrunning material through the machine.However, this slip is small and can be determined by the'ratio of theinside and outside diameter of the hollow r611 30. In rolling material,the slip is distributed between the surface of the roll 25, the innersurface of the roll 3!], the outer surface of the roll 30, the work, thework and the rolls l3 and 14. In the ordinary case, the thickness of theshell 30 is small with reference to its diameter. For example, where theouter diameter of the roll is 20 inches, the thickness of the roll willprobably not exceed one inch. Hence, the outer surface speed of the roll30 would be %3 or of the sur--- face speed of the roll 26,.assuming forthe moment there is no slip between the roll 26 and the inner surface ofthe hollow roll 30. It is obvious then that there is approximately 11%difference in surface speed to be accounted for. This will distributeitself through slip between the three surfaces mentioned above. By usinga roll 26 which is smaller than the rolls I3 and M, the outer surfacespeed of the roll 30 may be made equal to the surface speeds of therolls l3 and. I4. The diameter of the roll 25 for a condition of noslippage can be determined as follows:

The diameters of the fixed rolls l3 and M are the same and thus may beindicated as D1. The diameter of the roll 26 which we are seeking todetermine may be represented by Dx. The outside and inside diameters ofthe wrapping roll are known; therefore, designate the outside diameteras D; and the inside diameter as D3. Then If the work to be formed is ofsubstantial thickness, it may be desirable to take this into account incalculating the diameter Dx. If the thickness of the work is representedby T, then, in the formula, D4 will equal the outside diameter of thehollow roll plus twice the thickness T of the material.

It is evident that my hollow wrapping roll may be used to bend arcs orcircles of very large diameters on a bending machine which would nototherwise have sufilcient capacit, since the hollow roll can be of anydiameter without being limited by the capacity of the machine toaccommodate a roll centered on the shaft 25. The shroud plates 3| and 32need not be as large as the hollow roll 30 since their function ismerely to supportand guide the hollow roll 30 while the-roll 30 is freeto move normal to the :axis of shaft 25 without regard to the shroudplates. It is likewise obvious that since the sole function of theshroud plates is to constrain axial movement of the hollow roll, theshroud plates could be mounted on either of the fixed roll shafts l l orl2.

My hollow wrapping roll is likewise suitable for use on a standardwrapping machine, as shown in Figure 5, wherein the shafts 40, 4| and 42are positively driven through the gear train as diagrammatically shownin Figure 6. The fixed rolls 43 and 44 of the wrappingmachine are of thesame diameter. 45 is an ordinary wrapping roll which is concentric withthe shaft 42. The gearing shown in Figure 6 is proportioned to drive therolls 43, 44 and 45 at substantially the same surface speed. By using myhollow wrapping roll, as shown at 41, work of larger diameter than thewrapping roll 45 can be produced in the machine without changing thegear 48 in the gear train shown in Figure 6.

The considerations of slip will be the same as discussed for the pyramidbender and either the roll 45 may be selected of a proper diameter tdgive a condition of no slip between the hollow roll 41 and the rolls 43and 44, or the slip will distribute itself between the roll 45, theinner surface of hollow roll 41, the outer surface of roll 47 the workW,"and the work W and rolls 43 and 44.

It is theoretically possible to substitute a pinion gear for roll 26 andprovide the roll 30 with internal gear teeth to obtain a positive driveof the Wrapping roll. Because of obvious difliculties'in maintainingsuch gear teeth in mesh, the more practical scheme is to employ frictionsurfaces as I have shown in the drawings.

The machine shown in Figure 5 is a horizontal spindle machine. The shaft42 is carried on a slide 50 which may be "raised or lowered by suitablemeans, here illustrated as the screw 5|. As the hollow roll 41 'w illrest on the rolls 43 and 44, I have provided a carrier 52 to lift thehollow roll 41 with the slide 50. It is obvious that some such carrier,as 52, would be desirable in any type of horizontal spindle machine toprevent the hollow roll from dropping down on thelower roll or rollswhen feeding work into the machine.

In Figure 5 I have shown the shroud plate 49 mounted on the fixed rollshaft 40 to illustrate the flexibility of arrangement which my inventionpermits.

In Figure 7 I have shown my hollow roll 55 used similarly on a pinchtype bending machine. Figure 7 illustrates the use of a large roll 55with a shroud plate 56 of smaller diameter than the hollow roll 55.

The hollow roll of my invention can be made at a minimum cost as itrequires a minimum of material, the thickness of the wall of the hollowcylinder being governed solely by strength requirements which aregoverned by the weight of the material to be formed. I

Although I have shown and described a specific embodiment of my hollowroll for use on bending machines, it is obvious that various changescould be made in its form and proportions, which changes would be wellwithin the skill of 'the ordinary mechanic and yet would be embraced bythe spirit of my invention. I therefore wish to be limited only by thescope of the appended claims.

I claim:

1. A wrapping roll for a bending machine of the type having a pluralityof work engaging rolls mounted on substantially parallel roll shafts atleast some of which are drive shafts, said' wrapping roll comprising ahollow roll adapt-ed to be loosely mounted on one of said shafts, saidhollow roll having an outer surface defined as a surface of revolutionand adapted for forming the work in cooperation with the other workengaging rolls, and having an internal bearing surface adapted to engagesaid shaft throughout the work forming operation.

2. A wrapping roll for a bending machine -'0f the type having aplurality of work engaging rolls mounted on substantially parallel rollshafts at least some of which are drive shafts, said wrapping rollcomprising a hollow roll adapted to be loosely mounted on one of saiddrive shafts, said hollow roll having an outer surface defined as asurface of revolution and adapted for forming the work in cooperationwith the other work engaging rolls, and having an internal surfaceadapted to engage the outer surface of said drive shaft to be driventhereby throughout the work forming operation.

3. A wrapping roll for a bendingmachine having a power driven rotatingmember, said roll comprising a-hollow member having an internalcylindrical bearing surface adapted to be frictionally driven by saidrotating member, said internal surface having a greater diameter thansaid rotating member, and said roll having an external work surfacecomprising a surface of revolution generated about substantially thesame axis as the axis of said internal bearing surface.

4. A wrapping roll for a bending machine having a plurality of workengaging rolls and a driving member, comprising a hollow roll looselymounted on said driving member, said-hollow roll having an external worksurface comprising a surface of revolution about which said work isformed and an internal cylindrical bearing surface adapted to befrictionally engaged by said driving member, and means for constrainingaxial movement of said roll.

5. A conversion attachment for converting into a wrapping type bendingmachine a pyramid bending machine or a pinch bending machine having aplurality of work engaging rolls mounted on substantially parallel rollshafts at least some of which are drive shafts, comprising a hollowwrapping roll adapted to be loosely mounted on one of the driving rolls,said hollow roll having an outer surface defined as a surface ofrevolution and adapted for forming the work in cooperation with theother work engaging rolls, and having an internal surface adapted toengage the outer surface of said driving roll to be frictionally driventhereby throughout the Work forming operation.

6. A conversion attachment for a pyramid type bending machine having aplurality of cooperating metal bending rolls including a driving roll,comprising a hollow cylindrical member loosely mounted on said drivingroll and adapted to be internally driven by said roll, said memberhaving an external surface adapted to engage the metal to be bent, andmeans to retain said hollow member against substantial axial movementthereof.

7. A conversion attachment for a four roll pinch type bending machinehaving two driving rolls, comprising a hollow cylindrical member looselymounted on one of said driving rolls and adapted to be internally driventhereby, and means to retain said hollow member against substantialaxial movement thereof.

8; In a bending machine of the type having a plurality of work engagingrolls mounted on substantially parallel roll shafts at least some ofwhich are drive shafts, in combination, a hollow roll having an externalworking surface defined as a surface of revolution and adapted forformingthe work in cooperation with the other work engaging rolls, andhaving an internal bearing surface, said hollow roll being looselymounted on one of said shafts and being maintained in contact therewithduring the work forming operation by the pressure of said othercooperating rolls.

9. In a bending machine of the type having a plurality of work engagingrolls mounted on substantially parallel roll shafts at least some ofwhich are drive shafts, in combination, a hollow roll having an externalworking surface defined as a surface of revolution and adapted forforming the work in cooperation with the other work engaging rolls, andhaving an internal bearing surface, said hollow roll being looselymounted on one of said drive shafts and being maintained insubstantially line driving contact therewith during the work formingoperation by the pressure of said other cooperating rolls.

10. In a bending machine of the type having ,a plurality of workengaging rolls mounted on substantially parallel roll shafts at leastsome of which are drive shafts, in combination, a hollow roll having anexternal working surface defined as a surface of revolution and adaptedfor forming the work in cooperation with the other work engaging rolls,and having an internal bearing surface, said hollow roll being looselymounted on one of said shafts and being maintained in contact therewithduring the work forming operation by the pressure of said othercooperating rolls, and means to retain said hollow roll againstsubstantial axial movement.

11. In a bending machine having a plurality of work engaging rolls and ashaft, in combination, a hollow roll loosely mounted on said shaft, saidhollow roll having an outer surface defined as a surface of revolutionand adapted for forming said work in cooperation with said other rolls,an internal cylindrical bearing surface adapted to engage said shaft,and guide means for constraining axial movement of said roll.

12. In a pyramid bending machine having two fixed driving rolls, amovable driven spindle, and a third driving roll mounted on said movablespindle, in combination, a shroud plate carried ,by said movable spindlemounted at one end of said third driving roll, a second shroud platecarried by said movable spindle and mounted at the other end of saidthird driving roll, and a hollow roll loosely mounted between saidshroud plates and encircling said third driving roll.

13. In a bending machine of the class described, having a frame, atleast one rotating member mounted on said frame, a slide mounted on saidframe adapted for movement towards and away from said rotating member, asecond rotating member mounted on said slide, and means for moving saidslide, in combination, a hollow roll adapted to be loosely mounted onsaid second rotating member, and means independent of said secondrotating member carried by said slide for supporting said hollow rollwhen said slide is moved away from said first rotating member.

WILLIAM E. KANE.

